Field of the Disclosure
The present disclosure relates generally to wireless communication systems and, more particularly, to carrier aggregation of frequency bands in wireless communication systems.
Description of the Related Art
Carrier aggregation can be used to increase the uplink or downlink bandwidth for wireless communication between user equipment and one or more base stations. Carrier aggregation may be used in conjunction with multiple-input-multiple-output (MIMO) techniques. User equipment can signal their carrier aggregation or MIMO capabilities to the network using a standardized message such as a radio resource control (RRC) UE-EUTRA capability message. In the Long Term Evolution-Advanced (LTE-A) standard defined by the Third Generation Partnership Project (3GPP), user equipment can aggregate a primary component carrier with up to four secondary component carriers. Each of these component carriers can have a bandwidth of up to 20 MHz so that carrier aggregation can expand the bandwidth of the user equipment up to 100 MHz. The primary and secondary component carriers are selected from a predetermined number of frequency bands. The maximum number of EUTRA bands is 64 and the maximum number of supported carrier aggregation bandwidth classes per band is 16. For example, user equipment may support 16 EUTRA frequency bands that can be aggregated into 19 different combinations of a primary component carrier and a secondary component carrier. Other user equipment may support more frequency bands, more combinations of frequency bands, or aggregation of larger numbers of component carriers. The maximum number of combinations supported by user equipment that operate according to Rel. 10 LTE is 128, the number supported by Rel. 11 LTE user equipment is 256, and subsequent releases may allow user equipment to support more combinations.